package com.hotel_management_backstage.lin.utils.security;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.hotel_management_backstage.lin.entity.JwtUser;
import com.hotel_management_backstage.lin.model.LoginUser;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collection;

public class JWTAuthenticationFilter extends UsernamePasswordAuthenticationFilter {

    private ThreadLocal<Integer> rememberMe = new ThreadLocal<>();

    @Value("${jwt.TOKEN_HEADER}")
    private String TOKEN_HEADER;
    @Value("${jwt.TOKEN_PREFIX}")
    private String TOKEN_PREFIX;

    private AuthenticationManager authenticationManager;


    public JWTAuthenticationFilter(AuthenticationManager authenticationManager) {
        this.authenticationManager = authenticationManager;
        super.setFilterProcessesUrl("/api/login");
    }

    @Override
    public Authentication attemptAuthentication(HttpServletRequest request,
                                                HttpServletResponse response) throws AuthenticationException {
        // 从输入流中获取到登录的信息
        try {
            LoginUser loginUser = new ObjectMapper().readValue(request.getInputStream(), LoginUser.class);
            rememberMe.set(loginUser.getRememberMe() == null ? 0 : loginUser.getRememberMe());
            return authenticationManager.authenticate(
                    new UsernamePasswordAuthenticationToken(loginUser.getName(), loginUser.getPassword(), new ArrayList<>())
            );
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }

    }

    // 成功验证后调用的方法
    // 如果验证成功，就生成token并返回
    @Override
    protected void successfulAuthentication(HttpServletRequest request,
                                            HttpServletResponse response,
                                            FilterChain chain,
                                            Authentication authResult) throws IOException, ServletException {

        // 查看源代码会发现调用getPrincipal()方法会返回一个实现了`UserDetails`接口的对象
        // 所以就是JwtUser啦
        JwtUser jwtUser = (JwtUser) authResult.getPrincipal();
//        boolean isRemember = rememberMe.get() == 1;
        String role = "";
        //因为在JwtUser中存了权限信息，可以直接获取，由于只有一个角色就这么干了
        Collection<? extends GrantedAuthority> authorities = jwtUser.getAuthorities();
        for(GrantedAuthority authority : authorities){
            role = authority.getAuthority();
        }
        String token = JwtTokenUtils.createToken(jwtUser.getUsername(), role,false);
        // 返回创建成功的token
        // 但是这里创建的token只是单纯的token
        // 按照jwt的规定，最后请求的格式应该是 `Bearer token`
        response.setHeader("token", JwtTokenUtils.TOKEN_PREFIX + token);

        response.setContentType("application/json;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.write("{\"code\":\"200\",\"message\":\"登录成功\"}");
        out.flush();
        out.close();
    }

    // 这是验证失败时候调用的方法
    @Override
    protected void unsuccessfulAuthentication(HttpServletRequest request, HttpServletResponse response, AuthenticationException failed) throws IOException, ServletException {
//        response.getWriter().write("authentication failed, reason: " + failed.getMessage());
        response.setContentType("application/json;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.write("{\"code\":\"401\",\"message\":\"用户名或密码错误\"}");
        out.flush();
        out.close();
    }
}

